BP and its partners in the Macondo well that released an estimated 4.9 million gallons of oil over three months beginning in April 2010 should be required to inform state officials -- and the public -- of the toxic materials included in the spill, and the potential health effects of those materials, a three-judge appellate panel ruled in New Orleans on Wednesday. In winning the unanimous decision, the Center for Biological Diversity environmental group scored a rare partial victory before the U.S. 5th Circuit Court of Appeals in its attempts to pry more compliance with federal environmental laws out of BP in the aftermath of the Deepwater Horizon oil spill.

The federal appeals court agreed with U.S. District Court Judge Carl Barbier that most of the center's efforts to require BP to pay additional fines or otherwise be penalized for violations of the Clean Water Act; Comprehensive Environmental Response, Compensation and Liability Act; and Emergency Planning and Community Right-to-Know Act (EPCRA) under provisions of those laws allowing individuals to enforce them became moot when federal officials declared BP's Macondo well to be capped on July 15, 2010, and effectively "killed" on Sept. 19, 2010, by cementing its wellhole after being intercepted by a relief well.

"It's a very important victory that BP could be finally forced to publicly disclose all the toxic components it spilled into the waters, but we're disappointed by the dismissal of our Clean Water Act claims," said Miyoko Sakashita, oceans director for the center. "Throughout it all, we've insisted that those responsible for one of the worst environmental disasters in America's history should be held fully accountable for the profound damage they caused. The Gulf needs to be fully restored, both for the sake of its wildlife and for the people who depend on it for survival. We're certainly not there yet."

BP and other companies responsible for the spill still face a civil court proceeding over environmental fines and other actions required under the federal environmental laws, as part of the complex combination of lawsuits that have the federal government and attorneys representing private plaintiffs opposing them in court on Feb. 25.

But the court also ruled that Barbier incorrectly found to be moot a provision of the Right-to-Know Act that required BP to report what hazardous substances were released during the spill to state and local government authorities, including local emergency planning committees, with the information then made available to the public.

In opposing the appeal, BP attorneys argued that such information was being made available in the aftermath of the spill at various government web sites, but the three-judge panel was not persuaded by that argument.

"Our review of those web sites reveals a voluminous amount of information about the spill and the government's response, but the specific information required by EPCRA is not immediately apparent."

The ruling could require BP to reveal the hazardous materials involved in the spill and their health effects, and make the information public.

They found that the Right-to-Know Act specifically required the company to include "the name and estimated quantity of any substance involved in the release, the medium or media into which the release occurred, any known or anticipated acute or chronic health risks associated with the release, and the precautions to take as a result of the release."

Those notices are required to be maintained by the state's emergency response commission and must be made available to the public, they said.

In its suit, the center provided affidavits from members saying they'd been exposed to substances from the disaster, either through direct physical contact in the Gulf of Mexico or onshore, or through contact with fish and other wildlife.

"Those members averred that they were concerned about breathing air or ingesting water exposed to the substances and wanted to know what types of substances were involved in the Deepwater Horizon release so that they could assess the possible health effects of exposure," said the ruling.

"Here, however, BP has never claimed that it has at any time complied with EPCRA's reporting requirements for a written notice," the ruling said, and the company's failure to do so was a continuing violation of the law.

"An order from the district court that the defendants comply with EPCRA's reporting requirement for that release could therefore redress the center's claimed informational injury."

The ruling, written by Judge Carolyn Dineen King of Houston, Texas, and agreed to by Chief Judge Carl Stewart of Shreveport and Priscilla Owen of Austin, Texas, sends the case back to Barbier for further action. King was appointed by President Jimmy Carter, Stewart by President Bill Clinton, and Owen by President George W. Bush.